From patchwork Fri Oct 20 18:14:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13431002 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A475D2032B for ; Fri, 20 Oct 2023 18:14:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="edobgOcE" Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A872D5B for ; Fri, 20 Oct 2023 11:14:58 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5a7b10c488cso15612667b3.2 for ; Fri, 20 Oct 2023 11:14:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697825697; x=1698430497; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=NjxtAigxI0HmCKPvB9UmZgA+mMJTBsPd7/Wkgi0tm4s=; b=edobgOcEo2DQnIYa3i60Q0paZQLOBUFFJAspGON0iKv3guCLgQnv3MoUyA5m4XC6B2 1NnYrYOXf7ldJY7MtDeGWtmXcZF9gbcimkmUKsw4Tc+/ZndpptNZzqzFc2INZef6xm0S /RPkQNIfekKCAhsQeQyPYpRiEfVlt9Y+ca0Rd0NKmzHNBrEir/weWKIrwLexMzg+b/em uTi2rvaIE1haxah05bSE9QMepMX8j88AYAS3WXIXfMFnU4ehq2hiBJUE9kQ8VA/ylj4L P1eh2Z9KYUc9mDdpZ4aruyzZZzflvk8I95vWb8Nd8z0LiZSHIiZzBpJKO83k2jNizmiA fhWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697825697; x=1698430497; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=NjxtAigxI0HmCKPvB9UmZgA+mMJTBsPd7/Wkgi0tm4s=; b=acxHBS1NX5ulatE7PqRjHKiNe41+sHbDEeFy1/X2/YvImW/oeA0PJX3i3ezTj6lzDZ 0x7GLsmUBEY0h4DFPXsj3zloUkp8FxitfaKzfzHLe6B6MWUhIdGdCmkkPkEtM/qqmojL nvDKT1K5CNAPTKGLdY4+nLGwYDo7k+txi0osoo5ct+qgTZOCOTL52gcuHC4feytAwCtz q2EdBkIafQCuelqDzviWAyvPNVZ13bI4fcFxPMx/eOHCIEatVAHeGnx/utfMhhBFsMSN niQjbfbVc9F2pJoqzbN2pyBpfuciMCOuuaFnM3GGlHuXT8vHPjdua6Q1+83z2pj7F0cF Roww== X-Gm-Message-State: AOJu0YzIo/FT55wDZ6uztUQG255sbnQn4NAsq8zQUDiL4eHQkrEYvC2o GwPqtIuf9ZVgFht6lXs60jwZvlp8Q73+CAXROw== X-Google-Smtp-Source: AGHT+IF9SRE85ngks2gCtXwLYmkhJ3/uV8+grnXvrUYQkNHVHLP3fosnqqpIA3GEUwLdiQJy9CtyqVgplrjQH9jIsA== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a05:6902:1083:b0:d9a:6007:223a with SMTP id v3-20020a056902108300b00d9a6007223amr82297ybu.8.1697825697460; Fri, 20 Oct 2023 11:14:57 -0700 (PDT) Date: Fri, 20 Oct 2023 18:14:47 +0000 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAJbDMmUC/x2NUQrCQAwFr1LybWA3VUGvIiJumtaAbNekVkvp3 V38nAfzZgUXU3E4NyuYzOo65gpx1wA/7nkQ1K4yUKA2Bgrok2UuC3ams5hjGT9i6O9SngumF+3 jKdyqakOdGY+JOYZDz9QmqKfFpNfvP3i5btsPUwdLHoAAAAA= X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1697825696; l=2477; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=JmvkYA0HtU/j7JDgpCDudlk1OJo4lvEUsupF7z8hezA=; b=reN8ZCf+oaoqlz7W8BUFLMQjlrdg0RWOzYHkUPRlg80x9tWDd0LI/VU/0C9F7Cv4z62I3vr4S MgzW8oVQ0SgAYcyQOaq0PxhkKmOjOEfBBehIC/R/ncW9Ox0M3ys31Q7 X-Mailer: b4 0.12.3 Message-ID: <20231020-strncpy-drivers-power-supply-bq24190_charger-c-v1-1-e896223cb795@google.com> Subject: [PATCH] power: supply: bq24190_charger: replace deprecated strncpy with strscpy From: Justin Stitt To: Sebastian Reichel Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect bdi->model_name to be NUL-terminated based on its usage with sysfs_emit and format strings: val->strval is assigned to bdi->model_name in bq24190_charger_get_property(): 1186 | val->strval = bdi->model_name; ... then in power_supply_sysfs.c we use value.strval with a format string: 311 | ret = sysfs_emit(buf, "%s\n", value.strval); we assigned value.strval via: 285 | ret = power_supply_get_property(psy, psp, &value); ... which invokes psy->desc->get_property(): 1210 | return psy->desc->get_property(psy, psp, val); with bq24190_charger_get_property(): 1320 | static const struct power_supply_desc bq24190_charger_desc = { ... 1325 | .get_property = bq24190_charger_get_property, Moreover, no NUL-padding is required as bdi is zero-allocated in bq24190_charger.c: 1798 | bdi = devm_kzalloc(dev, sizeof(*bdi), GFP_KERNEL); Considering the above, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Kees Cook --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/power/supply/bq24190_charger.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: bb55d7f7f7445abcc8db50e6a65d4315e79f75c7 change-id: 20231020-strncpy-drivers-power-supply-bq24190_charger-c-6bcc105fc23b Best regards, -- Justin Stitt diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c index 3f99cb9590ba..1db290ee2591 100644 --- a/drivers/power/supply/bq24190_charger.c +++ b/drivers/power/supply/bq24190_charger.c @@ -1803,7 +1803,7 @@ static int bq24190_probe(struct i2c_client *client) bdi->client = client; bdi->dev = dev; - strncpy(bdi->model_name, id->name, I2C_NAME_SIZE); + strscpy(bdi->model_name, id->name, sizeof(bdi->model_name)); mutex_init(&bdi->f_reg_lock); bdi->charge_type = POWER_SUPPLY_CHARGE_TYPE_FAST; bdi->f_reg = 0;